In the Nine Mile Creek area, very extensive gypsum deposits are exposed in an area 1.5 kilometres in length across an average width of 400 metres. Gypsum outcrops in sink holes along the east bank of the Kootenay River and on both sides of Nine Mile Creek.

To the west, gypsum is in fault contact with older rocks and to the east it disappears under extensive overburden in the Kootenay River valley. Bedding generally strikes north to northeast with moderate to steep easterly dips. Gypsum of the Devonian Burnais Formation is intercalated with carbonate strata of the Devonian Cedared Formation. The gypsum is pale grey to grey in color and is typically laminated to thin-bedded.

At the Nine Mile showing, the gypsum is highly folded, and contains scattered lenses, blebs and irregular areas of white massive gypsum. The gypsum varies from cream to pure white in the north, to the more typical pale grey to grey in southern exposures. On the north side of the creek a 21 metre cliff composed of gypsum is exposed for 76 metres.

The quality of rock in the area is variable, with gypsum content varying from 44 to 94 per cent (Fieldwork 1988, p. 503). Sampling, by Butrenchuk, indicated gypsum contents between 81 and 97 per cent (Open File 1991-15).

A minor amount of gypsum was produced from the Little Joan quarry (082JSW005) at the north end of the Kootenay River - Nine Mile Creek area.

Westroc Industries Limited plan mining the gypsum deposits in the area.